Had the opposite experience on Shetland, apart from UK tourists.
The main road from Leverburgh to Tarbert then onto Stornoway is only really busy around ferry times. If you do the loop I mention above, get to Leverburgh about half an hour after the ferry’s arrived and you’ll have the road to yourself. The bit between Tarbert and Stornoway is busier as there’s the Uig-Tarbert ferry traffic as well but it’s a wide modern road so usually not a problem.
The Western Isles is popular with touring cyclists, we’ve done Barra to Tarbert a few years ago, so locals are used to it. Doesn’t mean to say there aren’t idiots though.
Edit: forgot about the wee frees 🙄